It [sleepiness] filled my brain like a cloud. I was going, going

It [sleepiness] filled my brain like a cloud. I was going, going...
A、Due to sleepiness, I was not aware that I had lost my sense of direction.
B、I was almost overcome by sleepiness and would doze off any moment.
C、I was trying hard to beat back sleepiness so that I could keep moving.
D、Sleepiness made me relaxed, as if I were walking under a cloud.
【正确答案】：B